Conductor



Jan. 5, 1937. J, J. GILBERT 2,065,525

' CONDUCTOR Filed March 29, 1929 FIG.

' INl ENTO/P J. J GILBERT ATTORNEY Patented Jan. 5, 1937 UNITED STATESPATENT OFFICE CONDUCTOR Application March 29, 1929, Serial No. 350,839

3 Claims.

This invention relates to electrical conductors and more particularly tostranded, braided or otherwise finely divided submarine cableconductors.

It has heretofore been proposed by others to use conductors fortelephone or carrier frequency submarine cables composed of a number ofstrands twisted or braided together in such a manner that each strandchanges its position at 10 intervals from the outer to the inner part ofthe conductor with each strand insulated from the others. A difficultyarises in connection with such conductors in case one or more strandsbecome broken and in accordance with the present invention it isproposed to overcome this difficulty by leaving off the insulation atsuitable intervals and conductively connecting all the strands togetherby means of a block of highly conductive material such as solder ormolten lead.

For reducing the increase of resistivity in a twin core conductor,generally designated proximity effect, it is also proposed in accordancewith the present invention to make up a conductor of a central coresurrounded by fiat tapes, the core and tapes being well insulated fromone another by copper or other oxide or other material so that currentwill not pass from one element of the conductor to another within thedistance of a single twist of the twin core pair. At intervals ofseveral twists the insulating material between the core and tapes isleft off so that the current will adjust itself in the case of a breakin the core of one or more but not all of the tapes.

The invention is further disclosed in connection with the accompanyingdrawing in which:

Fig. 1 shows a pair of twin cores;

Fig. 2 is a side view of one form of a conductor of the cores;

Fig. 3 is a cross section on the line 33 of 40 2? Fig. 4 is a. crosssection on the line 4-4 of Fig.2;

Fig. 5 is a side view of another form of a core conductor in which aplurality of discrete conduc- 45 tors or strands are braided orstranded;

Figs. 6 and 7 are cross sections on the lines 6--6 and l! respectivelyof Fig. 5.

The drawing is illustrative only and is not drawn to scale.

50 Fig. 2 discloses a copper conductor Ill having flat copper tapes orribbons I I surrounding a central core I2 of the usual type. Thesesurrounding tapes or ribbons are sometimes called surrounds. When suchconductors are employed in 5 a twin or multiple core cable such, forexample,

conductor cable.

I core cable may traverse the body of the conductor as the conductors oftwo cores I3 laid together as indicated in Fig. l, a desirable reductionof the increase in resistance known as proximity effect will be producedif the various surrounding tapes are lightly-insulated from each other,for example, by a layer of copper oxide N. In case one or more strandsbreak in service or during laying a difiiculty arises because of theloss of current fiow through the broken strand or strands over aconsiderable distance. In accordance with this 10 invention the centralcore and surrounding strands are insulated over the greater portion oftheir length but at intervals of several turns, for example, every 10 to1000 feet the oxide insulation is left off the core and strands so thatthey are in good conductive relation. If a break occurs the currentwillbe permitted to redistribute itself at the next point of conductiveconnection. The cross section of Fig. 4 indicates a point at which theinsulation I4 is omitted.

It is also within the scope of the invention to provide at intervals amore perfect conducting connection between the various conductor strandsthan is provided by merely leaving off the insulation.

An embodiment of this more perfect connection is illustrated in Figs. 5,6, and 7 which illustrate a conductor 01 the stranded type in which manylightly insulated strands are twisted or braided together to form aconductor suitable for voice or carrier frequency transmission.Preferably but not necessarily the several strands traverse the body ofthe conductor in such a manner as to pass at intervals from the interiorto the exterior surface. Such a conductor may be used in a singleconductor cable to reduce the increase in resistance known as the skineffect. In multiple conductor cables such as illustrated in Fig. 1, theconductors of which are stranded as shown in Figs. 5, 6 and 7, thediscrete strands may preferably but not necessarily traverse the body ofthe conductor in such a manner that they are all at the same averagedistance from the centers of the other composite conductors of themultiple Such multiple core cable conductors reduce the increase inresistance of the conductors with frequency known as proximity effects.When desirable the discrete conductors of the composite core conductorsof a multiple in such a manner as to pass at intervals from the interiorto the exterior surface so that all of the conductors taken over theentire length of the cable or any unit length thereof occupy the sameaverage distance from the center of the core and in addition traversethe core in such a manner that they are all at about the same averagedistance from the centers of the other composite coreconductors of themultiple core cable. In any such case the breaking of one or morestrands causes a loss of conductivity which is cured in the present caseby applying at suitable intervals a mass of lead or solder IS in goodconductive connection to the strands l6. Fig. 5 shows the conductor inside view at a point on line 'l-'! where the lead or solder is locatedand at a point on line G-6 where the conductive strands are insulatedfrom one another.

The lead or solder may be applied by cleaning a small portion of theconductor by an ordinary soldering flux or the like and dipping it inlead or solder just above the melting point, or in any other suitablemanner.

Conductors such as those illustrated are preferably to be employed inthe unloaded condition when properly insulated and armored. However,they may be loaded with a suitable layer of magnetic material toincrease the inductance. In case loading material is applied toconductors such as those of Fig. 5 the material l5 must have a meltingpoint suificiently high that the good conductive connection will remainafter the heat treatment of the loaded conductor. Compositions havingsuitably high melting points and sufficiently high conductivity areknown. An example is an alloy of about copper, 30% zinc having a meltingpoint of about 950 C.

It will be noted that in the case of transmission of relatively highfrequency currents over a twin core cable such as that of Fig. 1 withsolid conductors the magnetic fields of the currents in the twoconductors will react on one another to increase the eflfectiveresistance. In the case of a single core conductor such as that of Fig.5 the magnetic field of the current set up by the current in theconductor itself has a similar effect, known as the skin effect.

In each case the subdivided construction of the conductor tends toreduce this increase of resistance.

What is claimed is:

1. A composite submarine cable conductor composed of several discreteconductors insulated from one another throughout the major portion oftheir length and so interrelated that each discrete conductor in passingalong its length occupies successively diiierent radial positions fromthe approximate center to the approximate external surface of saidcomposite conductor but on the average lies at about the same radialdistance from the center as any other discrete conductor for the purposeof preventing an increase in the eiiective alternating currentresistance as the frequency increases, characterized in this, that atintervals the discrete conductors are in good conductive connection witheach other.

2. A cable conductor in accordance with claim 1 in which the conductiveconnection at intervals is composed of blocks of conductive material.

3. A multiple cable core having the core conductor of each core inaccordance with claim 1 for the purpose of decreasing skin eil'ect andfurther characterized in that the discrete conductors of each coreconductor occupy about the same average distance from centers of theother composite core conductors for reducing the increase of resistancewith increased frequency due to proximity effect".

JOHN J. GILBERT.

